Sonobuoy devices are widely employed for submarine detection purposes, and are also utilized for underwater geological exploration. Sonobuoys may be either active, wherein a transmitted signal is produced and the reflected signal is received, and transmitted, or the sonobuoy may be passive wherein signals are sensed and then sent to a distant processor.
In many standard configurations, a buoy system has a number of components stored inside a casing adapted to be dropped into the water, either from the air or a marine craft. The casing has a negative buoyancy which causes it to sink, and houses, among other things, a float deployment mechanism that is activated upon the casing entering the water and that will ride on the surface. As the casing sinks into the water, various components, including the sensor, are deployed therefrom, attached to the surface float by various lengths of cables. It is known that this type of buoy deployment system will set up a situation where surface-wave induced bobbing or drifting motion will cause flow noise to be detected by the sensor.
One known method of attempting to eliminate flow noise is to suspend the sensor from a neutrally buoyant float, that is linked via fiber-optic cable, to the antenna. Once the neutrally buoyant float has been deployed, and the sensor properly arranged in relation thereto, signals are transmitted via the fiber optical cable to the floating antenna. Practice has shown, however, that it is sometimes difficult to properly deploy the individual components of such a system without the fiber optic cable pack receiving damage. Although the system has two or three standard damper disks attached to a cabe to deploy beneath the buoyant can, these disks do not, in many instances, prevent this buoyant can from initially rising up to, or above, the fiber optical cable pack and bumping this pack and causing damage thereto or wrapping excess cable therearound. The instant invention provides the necessary drag on the buoyant can to cause it to initially maintain the nominal separation distance during the deployment, until the full complement of components is settled.